RANKING · 2020 CENSUS · 99 SHOWN OF 99

Fastest growing, Iowa counties · 2020

Iowa counties ranked by population growth from the 2010 census to 2020. This list covers the 99 counties in Iowa that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest shrinking Most population gained Most population lost Most densely populated Most sparsely populated

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION GROWTHVS 2000

01Dallas County, IAIA118,457+50.7%+37%

02Johnson County, IAIA160,044+16.8%+8%

03Polk County, IAIA516,546+14.3%−1%

04Warren County, IAIA57,331+13.4%+4%

05Story County, IAIA101,291+10.0%+30%

06Linn County, IAIA232,028+9.0%−34%

07Sioux County, IAIA36,774+6.4%+14%

08Dickinson County, IAIA18,077+6.2%−39%

09Dubuque County, IAIA99,381+6.0%+89%

10Scott County, IAIA175,259+5.7%+12%

11Madison County, IAIA17,270+5.5%−55%

12Clarke County, IAIA9,574+5.0%−51%

13Davis County, IAIA9,230+4.1%+48%

14Washington County, IAIA22,667+4.0%−26%

15Woodbury County, IAIA106,649+3.7%−35%

16Lyon County, IAIA12,354+3.0%−293%

17Bremer County, IAIA25,296+2.9%+31%

18Plymouth County, IAIA25,697+2.8%−54%

19Buena Vista County, IAIA20,449+2.8%+24%

20Calhoun County, IAIA9,562+2.7%−178%

21Jasper County, IAIA38,153+2.6%−62%

22Iowa County, IAIA16,504+1.9%−74%

23Henry County, IAIA19,349+1.7%−71%

24Boone County, IAIA26,799+1.6%−62%

25Wayne County, IAIA6,738+1.5%−131%

26Muscatine County, IAIA41,853+1.1%−75%

27Pottawattamie County, IAIA92,996+0.5%−91%

28Marion County, IAIA34,192+0.3%−95%

29Black Hawk County, IAIA131,532+0.0%−99%

30Jones County, IAIA21,253+0.0%−99%

31Cedar County, IAIA18,359+0.0%−99%

32Carroll County, IAIA20,303-0.3%+2782%

33Wapello County, IAIA35,210-0.5%−152%

34Mahaska County, IAIA21,880-0.9%−123%

35Grundy County, IAIA12,361-1.0%−135%

36Howard County, IAIA9,415-1.0%−181%

37Ida County, IAIA6,777-1.2%−81%

38Poweshiek County, IAIA18,368-1.3%+16%

39Marshall County, IAIA39,890-1.3%−149%

40O'Brien County, IAIA14,220-1.5%−32%

41Delaware County, IAIA17,674-1.6%−176%

42Clay County, IAIA16,202-1.7%+40%

43Winnebago County, IAIA10,251-1.7%−48%

44Jackson County, IAIA19,288-1.8%−205%

45Buchanan County, IAIA20,883-1.9%−257%

46Allamakee County, IAIA14,238-1.9%−132%

47Benton County, IAIA26,004-1.9%−115%

48Mitchell County, IAIA10,650-2.0%+296%

49Worth County, IAIA7,338-2.0%+99%

50Wright County, IAIA12,801-2.2%−575%

51Humboldt County, IAIA9,409-2.2%−36%

52Harrison County, IAIA14,623-2.3%−136%

53Cerro Gordo County, IAIA42,372-2.3%+279%

54Adair County, IAIA7,403-2.4%+23%

55Webster County, IAIA36,838-2.7%+906%

56Lucas County, IAIA8,847-3.0%−176%

57Guthrie County, IAIA10,782-3.0%−179%

58Union County, IAIA11,829-3.2%−9%

59Pocahontas County, IAIA6,819-3.2%−65%

60Crawford County, IAIA16,237-3.3%−435%

61Cherokee County, IAIA11,369-3.4%−55%

62Chickasaw County, IAIA11,663-3.4%+128%

63Shelby County, IAIA11,689-3.5%+703%

64Des Moines County, IAIA38,077-3.5%+469%

65Tama County, IAIA16,796-3.6%−191%

66Butler County, IAIA14,049-3.6%+32%

67Hardin County, IAIA16,455-3.7%+153%

68Montgomery County, IAIA10,002-3.8%+51%

69Mills County, IAIA14,793-3.8%−137%

70Hamilton County, IAIA14,944-4.0%−277%

71Floyd County, IAIA14,901-4.1%+348%

72Osceola County, IAIA5,980-4.2%+15%

73Appanoose County, IAIA12,077-4.4%+2663%

74Palo Alto County, IAIA8,899-4.5%−8%

75Page County, IAIA14,856-4.5%−820%

76Keokuk County, IAIA9,797-4.5%+136%

77Kossuth County, IAIA14,322-4.6%−40%

78Winneshiek County, IAIA19,733-4.7%−311%

79Hancock County, IAIA10,528-4.8%+13%

80Louisa County, IAIA10,416-4.8%−195%

81Van Buren County, IAIA7,131-4.8%−380%

82Monroe County, IAIA7,406-4.9%+308%

83Sac County, IAIA9,525-5.2%−20%

84Monona County, IAIA8,539-5.3%+3715%

85Clinton County, IAIA46,002-5.4%+210%

86Cass County, IAIA12,960-5.9%+102%

87Clayton County, IAIA16,845-6.0%+204%

88Greene County, IAIA8,658-6.1%−289%

89Franklin County, IAIA9,868-6.2%+7%

90Lee County, IAIA32,306-6.4%+292%

91Fayette County, IAIA19,047-6.6%−969%

92Taylor County, IAIA5,835-6.7%+204%

93Jefferson County, IAIA15,291-7.0%+786%

94Audubon County, IAIA5,509-7.3%+6%

95Adams County, IAIA3,617-8.1%+2%

96Emmet County, IAIA9,107-8.9%+89%

97Ringgold County, IAIA4,642-9.1%−1109%

98Decatur County, IAIA7,655-9.6%−328%

99Fremont County, IAIA6,522-11.2%+328%

SHOWING 1–99 OF 99

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU DECENNIAL CENSUS